In the United States, nearly half of all deaths in the adult population are due to cardiovascular disease. Coronary collateralization is a natural bypass system which is currently the target for new therapies to prevent myocardial damage from heart attack. This investigation will develop a new and advanced diagnostic MRI tool to detect early coronary collateralization and monitor the effect of a course of treatment to stimulate coronary collateralization. Recent studies have shown that certain growth factors increase the collateral circulation in chronic ischemia. In addition, the investigators have shown, using new MRI methods, that a course of growth factor treatment can achieve sufficient increase in collateralization to preserve normal cardiac function and avoid heart damage when a coronary artery occludes. Currently, there is no clinical test available to quantify the extent of collateralization before coronary occlusion occurs. Now, the medical treatment to stimulate coronary collateral development is possible, so a noninvasive clinical test to monitor and evaluate the treatment benefit is required. The investigators have developed a collateral-sensitized MRI method. In this investigation, they will compare the assessment of collateralization by collateral-sensitized MRI with assessment by invasive measures. The study will clarify how well early coronary collateralization can be characterized and monitored by the new collateral-sensitized MRI. It will examine the ability to detect changes in collateralization with time and will clarify associated physiologic changes. It will examine potentially confounding factors insufficiency collateral flow distribution. The collateral-sensitized MRI methods will be optimized for clinical application. This proposal is to validate the accuracy of collateral-sensitized MRI, study its ability to monitor growth factor effectiveness in an animal model, predict the functional benefits and further develop the new diagnostic tools to enable their clinical use with the new medical therapies to prevent myocardial damage from heart attacks.